1. Field of the Invention
The present invention relates to seals, and, more particularly, to seals for maintaining a sterile environment.
2. Description of the Related Art
Certain products, especially those in the pharmaceutical and food industries, require high degrees of sterility in the manufacturing process so the products are safe for users to consume. Manufacturing such products typically occurs in designated “clean rooms” where the environment and equipment is strictly controlled to prevent the introduction of foreign organisms and debris into the products during the manufacturing process. Maintaining the sterility in cleans rooms can be achieved by a combination of industry and government prescribed good manufacturing practices (GMP) and facility control to minimize the risk of contamination in the products.
Since maintaining the sterility of an entire room where many employees may be entering and leaving throughout a production run is often impractical, sterile products are typically produced in specially designed devices, such as bio-reactors, that are sealed to the outside environment. Introduction of material into the bio-reactor is limited to a few entryways so the risk of introducing foreign organisms and debris into the bio-reactor can be minimized. Each entryway is sealed when material is not being intentionally introduced to prevent contamination of the product inside the bio-reactor.
One particular problem with manufacturing products in a bio-reactor is the difficulty in mixing or otherwise agitating the sterile contents inside the bio-reactor. Typically the contents are agitated by a paddle or other instrument which is driven by a motor residing outside of the sterile environment. The agitating instrument is not typically left inside the bio-reactor during the entire production run, which can last months, as the contents of the bio-reactor can react with the material of the instrument and ruin the contents of the bio-reactor. Thus, the agitating instrument is usually only placed in the bio-reactor to agitate the contents at pre-determined intervals in the production run.
To maintain the sterile environment while the agitating instrument is being used to agitate the contents of the bio-reactor, a “pass-through” can be used that will seal against the moving surface of the agitating instrument to maintain the sterile environment. Known pass-throughs are effective to maintain sterility during one agitation of the bio-reactor contents, but must be replaced following agitation. This is inconvenient for manufacturing, since the pass-throughs must be replaced after each agitation, and also introduces another possible contamination event, since contamination can occur during the replacement process or the new pass-through might not be properly sanitized. Further, the contents of the bio-reactor may be held in sterile containers, such as polymer bags, within the bio-reactor and later transported to a different bio-reactor following agitation. Known pass-throughs do not allow the contents of the sterile bag to be agitated, transported to a different bio-reactor, and then agitated again, all while maintaining the sterile environment in the bag, without replacing the pass-through at least once.
What is needed in the art is a seal assembly for maintaining a sterile environment that can overcome some of the previously described disadvantages of known seal assemblies.